Deploy the prometheus-alerts helm chart on Azure Kubernetes Service (AKS)

Question

Pulumi · Accepted Answer

To deploy the `prometheus-alerts` Helm chart to an Azure Kubernetes Service (AKS) cluster using Pulumi, you'll follow several steps:

1. **Provision an AKS Cluster**: Before you can deploy any applications to AKS, you must have a running Kubernetes cluster. You can create an AKS cluster using the `azure-native` Pulumi provider, which allows you to declare the AKS cluster resource in code.
   
2. **Install the Helm Chart**: After the cluster is running, you will use Pulumi's Helm chart resource to deploy `prometheus-alerts`. Pulumi has built-in support for deploying Helm charts, making it easy to deploy third-party applications on your Kubernetes cluster.

Here's a high-level overview of the Pulumi program you will write:

- Set up the Azure provider.
- Create a new AKS cluster using the `azure-native.containerservice:ManagedCluster` resource.
- Configure the Kubernetes provider to use the credentials from the created AKS cluster.
- Deploy the `prometheus-alerts` Helm chart using the `kubernetes.helm.v3.Chart` resource.

Below is a Pulumi program written in TypeScript that accomplishes the deployment:

```typescript
import * as pulumi from "@pulumi/pulumi";
import * as azure_native from "@pulumi/azure-native";
import * as k8s from "@pulumi/kubernetes";

// Create an AKS Cluster
const resourceGroup = new azure_native.resources.ResourceGroup("aksResourceGroup");

const aksCluster = new azure_native.containerservice.ManagedCluster("aksCluster", {
    // Setting the Azure region and the resource group for the AKS cluster
    resourceGroupName: resourceGroup.name,
    location: resourceGroup.location,
    // Configuring the properties of the AKS cluster
    agentPoolProfiles: [{
        count: 2, // Specify the number of nodes (VMs) to create
        vmSize: "Standard_DS2_v2", // Specify the size of the VM
        mode: "System",
        name: "agentpool",
    }],
    dnsPrefix: "aksk8s", // Prefix for the FQDN for the master pool
    enableRBAC: true, // RBAC is enabled for secure interaction with the cluster
});

// Get the kubeconfig from the cluster for connecting to the cluster using kubectl
const creds = pulumi.all([aksCluster.name, resourceGroup.name]).apply(([clusterName, rgName]) => 
    azure_native.containerservice.listManagedClusterUserCredentials({
        resourceGroupName: rgName,
        resourceName: clusterName,
    })
);

// Extract the kubeconfig and store it in a Pulumi output
const kubeconfig = creds.kubeconfigs[0].value.apply(c => Buffer.from(c, "base64").toString());

// Create a Kubernetes provider instance using the kubeconfig
const k8sProvider = new k8s.Provider("k8sProvider", {
    kubeconfig: kubeconfig,
});

// Deploy the Prometheus Alerts Helm chart using the Kubernetes provider
const prometheusChart = new k8s.helm.v3.Chart("prometheus-alerts", {
    // Reference to the chart to be deployed
    chart: "prometheus-alerts",
    // Specify the repository holding the chart
    fetchOpts: { repo: "https://prometheus-community.github.io/helm-charts" },
    // Set the values for the Chart. This will depend on the values specified by the Chart's authors
    values: {
        alertmanager: {
            config: {
                // Your AlertManager configuration here
            },
        },
        server: {
            persistentVolume: {
                // Configure persistent storage if needed
            },
            // Other configurations as needed
        },
    }
}, { provider: k8sProvider });

// Export the URL of the Prometheus server
export const prometheusServerUrl = pulumi.interpolate `http://${prometheusChart.getResourceProperty("v1/Service", "prometheus-alerts-server", "status").apply(s => s.loadBalancer.ingress[0].hostname)}/`;
```

### Understanding the Program:

- The `resourceGroup` is a logical container in which all Azure resources are deployed.
- The `aksCluster` defines the AKS cluster configuration, including the number and size of nodes.
- The `creds` and `kubeconfig` are used to authenticate against the AKS cluster using Kubernetes credentials.
- The `k8sProvider` is the Kubernetes provider configured with the cluster's kubeconfig, so you can deploy applications.
- The `prometheusChart` uses the Helm provider to deploy the chart from the Prometheus Community Helm repository to your AKS cluster.

Keep in mind that while Pulumi takes care of deploying the application, you'll need to handle networking considerations, like making the Prometheus server accessible to external traffic, properly. The example above assumes there is a LoadBalancer service in Prometheus Chart which would assign an external IP or hostname. In a real-world scenario, you may want to set up an Ingress controller or other network resources to properly manage access.

Make sure you have the Helm chart's values file configured correctly for your particular needs. You can look up the necessary values for your Prometheus deployment in the chart's documentation in the linked repository.

After writing the program:

- Run `pulumi up` to start the deployment. Pulumi will print out the status of the resources being provisioned.
- Once done, it will output any stack exports you have specified—here, the URL to access the Prometheus server.

Remember that deploying infrastructure with Pulumi will incur costs associated with the resources being used on your Azure account, so make sure you understand the pricing and clean up resources with `pulumi destroy` if they are no longer needed.